Subgrid parameterisations for high resolution atmospheric flows

Vassili Kitsios, Jorgen Frederiksen, Meelis Zidikheri

Abstract


Numerical and computational methods are developed for the Large Eddy Simulation of atmospheric flows on a sphere with a spectral quasigeostrophic model. The subgrid scales of motion are parameterised using a net eddy viscosity that is derived from a high resolution reference Direct Numerical Simulation with $504$~zonal and total wavenumbers or $1536 \times 768$ grid points (longitude by latitude). Simulations are undertaken for a wide range of truncation wavenumbers to determine the influence of resolution on the net eddy viscosity. A universal scaling law for these coefficients is established for application to large eddy simulations of more general geophysical flows.

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Keywords


large eddy simulation; stochastic subgrid modelling

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DOI: http://dx.doi.org/10.21914/anziamj.v52i0.3800



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